Drill Bit Sizes for Wood Screw Pilot Holes
Unless you enjoy multiple trips to the hardware store, a pilot hole is essential for all wood screws. Not only do pilot holes prevent the wood from splitting, but they also reduce the likelihood of breaking the screw. Thus, drilling pilot holes will help you save on the materials cost and offer a better appearance to your final product. To save you time, our quick reference chart above will tell you which drill bit to use for a given screw size. The chart is specific for tapered wood screws, which are traditional American wood screws with a steel core. If you’re working with a different type of screw, we have some exception guidelines for you below. In the case that you’re drilling into metal, glass, or plastic, you should continue searching for another drill bit chart.
Drilling Holes for Different Screw Types
- For newer non-tapered screws, we generally recommend going up at least 1 drill bit size. Otherwise, you’ll find that the screw will become overly resistant as it gets deeper into the pilot hole. Non-tapered screws include drywall screws & some appearance wood screws.
- If you’re working with brass screws, go up 1 size as well to accommodate the softer metal. Brass isn’t the only exception here—any wood screw made of a material that’s softer than steel should go up a size as well. When working with brass wood screws, an insufficiently sized pilot hole stresses the screw in two ways. First, the screw is more prone to stripping, which renders an ugly appearance. This will also limit your ability to remove the screw in the future. Secondly, the head of the screw is more likely to snap, which we all know is undesirable.
In the event that you encounter both exceptions listed above, go up two drill bit sizes. For instance, a non-tapered brass screw that’s size # 6 would use 3/32″ drill bit for softwood & 7/64″ drill bit for hardwood. That allows for us to accommodate both the softer material and the non-tapered screw tip. With that being said, you may need to go up more sizes depending on other factors. The ultimate indicator that your pilot hole is too small is that the screw is too hot to touch with your bare skin. And for the record (and legal reasons), we don’t recommend touching a screw until it’s cooled to room temperature. Once it has, you may remove the screw and expand the diameter of the pilot hole.
Determining the Correct Drill Bit Size
When referencing the chart above, please know that we were conservative with our drill bit assignments. As all wood workers know, it’s always easier to remove more wood than to try to replace it. Also, if you’re worried about not having the smaller drill bits, we have good news for you. The smaller screw sizes are generally for precision applications, which most home improvement projects won’t require. But in the case that you do enjoy a second trip to the hardware store, you still may want to pick up some smaller drill bit sizes on your next visit.
Recommended Tools for Drilling Pilot Holes:
DEWALT Titanium Pilot Point Drill Bit Set
Why we like it:
- Drill bits feature tapered tips for greater strength
- Titanium coating provides greater longevity
- Complete coverage for all wood screw sizes
- Works for wood, plastic, & metal
- Shanks have flattened side to prevent slipping
DEWALT Cordless Power Drill
Why we like it:
- Handles well with no latency in power
- Compact size fits into tight spaces
- Impressive battery life with backup included
- LED light illuminates dark areas when drilling
- When it comes to power drills, stick to quality brands
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